ReWaterDesign – Free Calculator for Water Reuse
Optimize the use of greywater and rainwater, according to the UNE-EN 16941 standard
This calculator allows you to assess the water reuse potential in residential homes according to the UNE-EN 16941 standard, taking into account greywater and rainwater.
✓ EN 16941 Standard • ✓ Actual weather data • ✓ Clear and understandable presentation
ℹ️ Calculator primarily intended for residential homes. For larger projects, a specific report can be generated.
🌧️ Calculator EN 16941-1: Rainwater Recovery
Rainwater Calculator
This calculator analyzes precipitation data from the last 5 years of your location to determine the optimal storage volume and expected coverage.
Roof surface that collects rainwater (length × width)
Amount of rainwater you want to use each day (WC, irrigation, etc.)
• Roof runoff coefficient: 80% (losses by evaporation/absorption)
• Hydraulic system efficiency: 90% (piping/filter losses)
Calculated Rainwater Production
Uses for Rainwater
🔘 Calculator EN 16941-2: Grey Water Reuse
General Data
Treatment Method
Efficiency includes losses from treatment, storage and distribution
Uses for available greywater:
📊 Integrated Results and Water Savings
🔘 Captured and Treated Grey Water
- Shower: 0 l/d
- Bathtub: 0 l/d
- Washbasin: 0 l/d
- Washing machine: 0 l/d
- Total Captured: 0 l/d
- Treatable greywater: 0 l/d
⚫ Waste Water and System Losses
- WC: 0 l/d
- Sink: 0 l/d
- Dishwasher: 0 l/d
- Pool (50%): 0 l/d
- Treatment losses: 0 l/d
- Excess greywater: 0 l/d
- Total Blackwater: 0 l/d
🟢 Other Uses of Recovered Water
- Irrigation: 0 l/d
- Pool (50% evap.): 0 l/d
- Car washing and Floor cleaning: 0 l/d
- Total Others: 0 l/d
🌧️ EN 16941-1: Rainwater Recovery
- Not yet calculated
Rainwater Used: 0 l/d
Excess Rainwater: 0 l/d
* This calculator applies: greywater first, rainwater second. In practice, the order depends on specific technical criteria of the project.
🔘 EN 16941-2: Grey Water Reuse
Demand:
- Not yet calculated
Greywater Reused: 0 l/d
Tank volume normally sufficient: 0 liters
Excess Greywater: 0 l/d
These responses are based on the standards BS EN 16941-1:2024 y BS EN 16941-2:2021, , available on the official BSI portal (paid download).
📈 Total Daily Consumption and Savings Calculation
TOTAL DAILY CONSUMPTION: 0 l/d
SAVINGS BY REUSE (UNE 16941-2): 0 l/d
SAVINGS BY RAINWATER RECOVERY (UNE 16941-1): 0 l/d
INTEGRATED NET CONSUMPTION: 0 l/d
